1. Field of the Invention
This invention is in the field of lifts mounted to vehicles.
2. Description of the Prior Art
Devices have been provided for raising and lowering invalids and other persons confined to wheelchairs relative to the ground and a vehicle such as a van. Two such devices are disclosed in the U.S. Pat. No. 3,710,962 issued to Fowler and U.S. Pat. No. 3,847,292 issued to Williams and Gates. Likewise, other types of lifting devices have been provided for raising and lowering freight relative to the transport vehicle. For example, see the U.S. Pat. No. 3,371,805 issued to Himes, U.S. Pat. No. 3,416,677 issued to Abfalter and U.S. Pat. No. 3,776,402 issued to Bryan.
A main objective in designing a lift for a handicapped person is for the lift to be low in cost and readily mountable to a vehicle such as a van without requiring extensive modifications to the vehicle. Many of the prior art devices are relatively complicated having a variety of hydraulic systems for raising and lowering the handicapped person. Likewise, the lift must be designed to mount at both the back doors and side doors of the van. Another main objective is to provide a fail-safe capability. That is, there should be a positive linkage between the actuator and the moving members which prevents the lift from falling in the event that the drive chain or hydraulic system fails. The fail-safe design should also provide a manual capability to lower the lift in the event of failure of the drive chain. Disclosed herein is a new and improved lift which solves the aforementioned problems.